Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for Douglas, AZ

Douglas, AZ is in USDA zone 8a across its 3 ZIP codes. The median last spring frost is March 18 and the first fall frost November 13.

Douglas on the zone map

Outlined: its 2 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone8a10 to 15 °F
ZIP codes3
Last frostMar 18
First frostNov 13
Growing season235 days

8a 3 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Douglas, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMarch 18median — 50% chance of a later frost
Safe for tender plantsApril 12only 10% chance of frost after
First fall frostNovember 13median — 10% chance by Oct 27
Growing season235 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 27 and returns around November 25.

From the NOAA station Douglas, AZ, elevation 4,039 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in Douglas

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 4 – Feb 18
SpinachSow outdoors · Feb 4 – Feb 25
Broccoli, cabbageStart indoors · Jan 7 – Jan 21
Broccoli, cabbageTransplant · Feb 25 – Mar 11
Onion setsPlant outdoors · Feb 18 – Mar 4
PotatoesPlant outdoors · Feb 25 – Mar 11
LettuceSow outdoors · Feb 18 – Mar 4
Carrots, beetsSow outdoors · Feb 25 – Mar 11
TomatoesStart indoors · Jan 21 – Feb 4
TomatoesTransplant · Mar 25 – Apr 8
Peppers, eggplantStart indoors · Jan 7 – Jan 21
Peppers, eggplantTransplant · Apr 1 – Apr 15
BeansSow outdoors · Mar 25 – Apr 8
Sweet cornSow outdoors · Mar 25 – Apr 8
Cucumbers, squashSow outdoors · Mar 25 – Apr 8
Fall lettuce, spinachSow outdoors · Sep 18 – Oct 2
GarlicPlant cloves · Oct 30 – Dec 4
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Mar 18) and first fall frost (Nov 13) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 85608 came on Feb 1 — about the same time as the 1991–2020 average (Feb 3).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 8a in Arizona

472 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. Each links to its USDA PLANTS profile.

Trees 24

Arizona cypress50 ft · blooms spring · low shade tolerance · to −23 °FArizona madrone30 ft · blooms late spring · high shade tolerance · to −4 °FArizona sycamore80 ft · blooms early spring · high shade tolerance · to −8 °FArizona walnut50 ft · blooms late spring · high shade tolerance · to −33 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °F

Shrubs 100

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican tarwort3 ft · blooms late spring · high shade tolerance · to −23 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FApache plume6 ft · blooms late spring · high shade tolerance · to −23 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 195

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 144

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °FArizona cottontop4 ft · blooms late summer · high shade tolerance · to −13 °FArizona fescue2 ft · blooms late spring · high shade tolerance · to −23 °F

Vines 1

western white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Douglas, AZ.

Soil in Douglas, AZ

The soil mapped at the center of ZIP 85608 is Bonita — loam, well drained.

TextureLoama good balance for most vegetables
pH7.6slightly alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter2%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classFarmland of unique importanceUSDA classification

Map unit: Bonita-Forrest complex, 1 to 8 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 85608; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Douglas, AZ

Summer high96 °Faverage high, June
Winter low28 °Faverage low, January
Hot days111days a year at 90 °F or more
Freezing nights75nights a year at 32 °F or less
Growing degree days5,020base 50 °F — the season’s usable heat
Longest day14 h 12 mindaylight on June 21
Shortest day10 h 06 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation14 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 62 °F, low 28 °F 62°28° JanFebruary: average high 66 °F, low 32 °F 66°32° FebMarch: average high 72 °F, low 36 °F 72°36° MarApril: average high 79 °F, low 42 °F 79°42° AprMay: average high 87 °F, low 50 °F 87°50° MayJune: average high 96 °F, low 60 °F 96°60° JunJuly: average high 94 °F, low 65 °F 94°65° JulAugust: average high 92 °F, low 64 °F 92°64° AugSeptember: average high 89 °F, low 58 °F 89°58° SepOctober: average high 82 °F, low 47 °F 82°47° OctNovember: average high 71 °F, low 35 °F 71°35° NovDecember: average high 61 °F, low 28 °F 61°28° Dec

Precipitation by month inches

0″1″2″3″4″January: 0.78 in precipitation 0.8 JanFebruary: 0.61 in precipitation 0.6 FebMarch: 0.85 in precipitation 0.8 MarApril: 0.24 in precipitation 0.2 AprMay: 0.26 in precipitation 0.3 MayJune: 0.54 in precipitation 0.5 JunJuly: 3.04 in precipitation 3.0 JulAugust: 3.38 in precipitation 3.4 AugSeptember: 1.41 in precipitation 1.4 SepOctober: 0.98 in precipitation 1.0 OctNovember: 0.68 in precipitation 0.7 NovDecember: 1.21 in precipitation 1.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Douglas Bisbee Inl Airport, AZ (within 1 mile); precipitation: Douglas 8.8 Nnw, AZ (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Douglas

856078a
10 to 15 °F
856088a
10 to 15 °F
856558a
10 to 15 °F

Arizona planting zones →

Questions about Douglas

What planting zone is Douglas, AZ?

Douglas, AZ is in USDA hardiness zone 8a on the 2023 map (8a: 10 to 15 °F).

When is the last frost in Douglas, AZ?

The median last spring frost is March 18 and the median first fall frost is November 13 (NOAA 1991–2020 normals, Douglas station).

When can I plant a garden in Douglas, AZ?

Cool-season crops like peas and spinach go in around Feb 4 – Feb 25; tomatoes, peppers, beans and squash after about Mar 25, once frost risk has passed.

What kind of onions grow in Douglas, AZ?

Short-day onions: the longest day is 14 h 12 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

How much rain and snow does Douglas, AZ get?

About 14 inches of precipitation a year (NOAA 1991–2020 normals).